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Total 7 documents matching your query.

1. [TowerTalk] Protection of a preamp (score: 1): Author: Lizeth Norman <normanlizeth@gmail.com>; Date: Tue, 21 Jan 2014 11:14:16 -0500; Hi all! I have a preamp that I switch in and out with a pair of spdt coaxial relays. The NC positions pass through and the NO positions hold the preamp. The relays are +24Vdc and the preamp needs ide; /archives//html/Towertalk/2014-01/msg00289.html (7,700 bytes)
2. Re: [TowerTalk] Protection of a preamp (score: 1): Author: "Patrick Greenlee" <patrick_g@windstream.net>; Date: Tue, 21 Jan 2014 10:25:08 -0600; Well that is one way. Another is to use a (one, 1 , ein un) Zener diode to subtract out the difference. Another way is to measure the current draw of the amps when operated on proper voltage and then; /archives//html/Towertalk/2014-01/msg00291.html (9,101 bytes)
3. Re: [TowerTalk] Protection of a preamp (score: 1): Author: TexasRF@aol.com; Date: Tue, 21 Jan 2014 11:31:03 -0500 (EST); Norm, yes, there are dragons here! Relay isolation has to be sufficient keep the rf voltage from destroying the preamp. Often times a single relay doesn't give enough isolation and tandem relays are; /archives//html/Towertalk/2014-01/msg00292.html (8,355 bytes)
4. Re: [TowerTalk] Protection of a preamp (score: 1): Author: Tony Brock-Fisher <barockteer@aol.com>; Date: Tue, 21 Jan 2014 12:46:26 -0500; I think a 12 volt 3 terminal regulator is a better idea, and it would protect against coil spikes as well. With one IC and two caps it's still fewer parts than 20 diodes. To protect the preamp, use a; /archives//html/Towertalk/2014-01/msg00296.html (7,407 bytes)
5. Re: [TowerTalk] Protection of a preamp (score: 1): Author: "Patrick Greenlee" <patrick_g@windstream.net>; Date: Tue, 21 Jan 2014 13:15:10 -0600; Back diodes across the coils wouldn't hurt. Patrick NJ5G I think a 12 volt 3 terminal regulator is a better idea, and it would protect against coil spikes as well. With one IC and two caps it's still; /archives//html/Towertalk/2014-01/msg00298.html (8,772 bytes)
6. Re: [TowerTalk] Protection of a preamp (score: 1): Author: Chuck Smallhouse <w7cs@theriver.com>; Date: Tue, 21 Jan 2014 14:09:30 -0700; To add to Gerald's very experienced comments, the addition of a sequencer is highly recommended, especially if the last stage/sequence of it will control the "RF Inhibit" function of your transceiver; /archives//html/Towertalk/2014-01/msg00303.html (9,426 bytes)
7. Re: [TowerTalk] Protection of a preamp (score: 1): Author: "Dan Schaaf" <dan-schaaf@att.net>; Date: Tue, 21 Jan 2014 16:35:40 -0500; Now, all you need to worry about is a lightning strike. Hopefully your preamps short the input to ground when powered down. And a fuse resistor of about 22 ohms 1/8 watts in series between the antenn; /archives//html/Towertalk/2014-01/msg00304.html (10,086 bytes)

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